This invention relates generally to imaging methods and apparatus, and more particularly to methods and apparatus using computed tomography (CT) data.
Characteristics of an individual, such as body weight, height, girth, gender, age, etc. are clinical descriptors useful by physicians to predict certain risks, for example, mortality and morbidity risk. Metrics such as Body Mass Index (BMI) and Lean Body Weight (LBW) that account for body fat composition may provide even better information to predict the risk of mortality and morbidity for a particular individual, as well as provide a more accurate parameter for an appropriate tailoring of pharmacologic interventions.
BMI is a measure of body fat based on height and weight that applies to both men and women. LBW is a person's total body weight minus the weight of adipose tissue (fat). LBW is generally estimated using a body composition weight analyzer scale that measures leg-to-leg bioelectrical impedance. However, these estimates can be affected by several compounding factors, such as an individual's hydration status or the amount of fluid in the urinary bladder and small bowel loops. The greater the error in the estimate, the greater the likelihood that, for example, the dose and rate of an administered contrast medium is not correct or optimal for a patient. Thus, imaging quality may be adversely affected, for example, when performing a CT image scan of a person injected with a contrast medium. Moreover, administering too much contrast agent can result in increased risk and severity of contrast-induced allergic reactions. Additionally, routine assessments of leg-to-leg impedance may not be practical in standard clinical practice.